condition mean min max ZT0-3 20.866175 19.9096 21.82275 ZT4-7 22.757649999999998 22.757649999999998 22.757649999999998 ZT8-11 26.24625 26.24625 26.24625 ZT12-15 0 0 0 ZT16-19 40.5753 40.5753 40.5753 ZT20-23 36.48915 36.48915 36.48915